The present invention relates to photographic apparatus in general, especially to still cameras, and more particularly to improvements in photographic apparatus of the type which can accept different types of films and are provided with means for automatically compensating for different characteristics of photographic films, especially for different sensitivities or speeds of films.
It is known to provide cassettes or analogous containers for photographic film with indices or markers which designate the speed or sensitivity of film in the container. A marker may constitute a protuberance, a notch, a notch and a protuberance, the absence of a notch or the absence of a protuberance. A camera which utilizes such containers is provided with spring-biased scanning means (e.g., a lever, a slide or an analogous sensor) which bears against the marker of a properly inserted container and thereby automatically sets the camera for operation with the selected type of film. For example, the scanning means can move (or can allow the movement of) a filter behind the picture taking lens when the camera is loaded with film having a first sensitivity, and the filter is moved (or allowed to move) out of register with the lens when the camera contains film having a different second sensitivity.
A drawback of the just described photographic apparatus is that the force with which the scanning means bears against the index or marker of a container is likely to move the container from a predetermined optimum position, i.e., successive foremost unexposed film frames are not always located in a predetermined film plane at an optimum distance from the picture taking lens. This results in the making of unsatisfactory exposures.